Do we know what Cubaryi's deal was? Like, did she know who Kaldena was or did she just decide to follow her just because? I don't think Kaldena bought her or that she just latched onto the opportunity to join a conspiracy because her loyalty and motivations seem too genuine for that. I also don't think she just lost faith in the Order/gods at some point, although mostly just because it seems too simple and doesn't match the narrative. I can think of three options that are equally interesting to me:
Her loyalty primarily lies with Kaldena, rather than the Order. She was willing to follow Kaldena with all her heart, even if she strays from the path set for her.
She's actually part of the Moonshade Order. Kaldena's goals were a convenient stepping stone and her own ideals lie somewhere else entirely.
Yuri